98 Boxster engine noise diagnosis

[jcm55]

My son and I bought this 1998 Boxster on Wednesday. 157K miles. There is an intermittent chirp-chirp-chirp noise that varies in frequency with RPMs. Sometimes it does it consistently at idle, other times not at all. Doesn’t seem to matter if engine is cold or hot. I thought perhaps the serpentine belt or a pulley, but it doesn’t seem to be those when we had the access panel behind the seats off.

Does anyone recognize the sound? You can hear it best toward the end of the video.

https://youtube.com/shorts/PFvW5ZD0f1A?si=a85IHvFmHcwn0gEr

[tonythetarga]

Pull the coil packs off of the car and check the spark plugs. If they are loose at all, they will chirp like that. Good luck.

[jcm55]

Thanks — I found an older thread here with a video that had the exact same noise, which turned out to be a loose spark plug as you suggested. We replaced the plugs and coil packs. No more chirp now.

[tonythetarga]

Thanks for reporting back. Good for future reference for another Pelicanhead trying to solve the same issue. ��